PIES LHD Magnetic Field Reconstruction

Reconstructions of the magnetic fields in the Large Helical Device (LHD) by the Princeton Iterative Equilibrium Solver (PIES) code are presented. The pressure profile for the device is experimentally determined from Thomson scattering. Magnetic diagnostics provide magnetic field constraints. Initial conditions are provided by the Variational Moments Equilibrium Code (VMEC). The pies code is then utilized to study magnetic island formation and stochastic regions in the stellarator. Mechanisms for flux surface breakup in stellarators are investigated. These results provide additional benchmarks for comparisons to other equilibrium codes (such as HINT2).